If you're running a VQ-powered Nissan or Infiniti and looking to free up real power, the ISR Performance HGC Long Tube Headers are a direct bolt-on upgrade designed specifically for the 350Z, 370Z, G35, and G37 platforms. Stepped primaries, stainless construction, and a high ground clearance collector design make this a practical upgrade for daily driven, track, and drift applications.
What It Is
The ISR Performance HGC Long Tube Headers are a pair of long tube exhaust headers built for VQ35DE and VQ35HR engines. They are constructed from 304 brushed stainless steel with heavy duty flanges. The "HGC" in the name stands for High Ground Clearance, which refers to the collector positioning. The collectors are designed to sit higher than traditional long tube designs so the headers don't hang low under the car, which is the biggest complaint about most long tube options for this platform.
What It Does
These headers replace the restrictive factory exhaust manifolds with a long tube design that improves exhaust scavenging across the entire power band. The stepped primary design is the key feature here. Stepped primaries use two different pipe diameters within each runner, starting smaller and transitioning to larger, which helps retain low and mid range torque while still allowing strong top end horsepower gains. This is important on a VQ35 because a lot of aftermarket headers sacrifice low end drivability for peak power. These don't.
Expect noticeable gains in throttle response, torque through the midrange, and peak horsepower. The long tube design also pairs well with other bolt-ons like a high flow Y-pipe and cat-back exhaust.
Fitment and Compatibility
The ISR HGC Long Tube Headers fit the following vehicles:
- Nissan 350Z (VQ35DE and VQ35HR)
- Nissan 370Z (VQ37VHR, fitment confirmed)
- Infiniti G35 (VQ35DE and VQ35HR, including G35X AWD)
- Infiniti G37 (VQ37VHR, including G37X AWD)
The G35X and G37X AWD variants are confirmed to work with these headers. Each header includes two O2 sensor bungs placed downstream of the collector so you can retain your factory upstream and downstream O2 sensors. You will need to extend your primary O2 sensor harness (VQ37 version) to reach the new bung location, which sits lower on the header than the factory location.
Who This Is For
These headers are aimed at VQ owners who want serious power gains without the downsides of typical long tube headers. If you've been avoiding long tubes because you're worried about ground clearance on speed bumps, driveways, or track curbs, the HGC design directly addresses that. If you're running a built motor or boost and need headers that can support higher power levels, the 304 stainless construction and heavy duty flanges are rated for it. If you want a header that doesn't kill your torque response in daily driving, the stepped primary design matters.
What's in the Box
The kit ships complete with everything needed for installation:
- 2x Stainless steel long tube headers
- 2x 2-bolt exhaust gaskets
- 2x Head to manifold gaskets
- 4x O2 sensor bung plugs
- 4x Exhaust nuts
- 4x Exhaust bolts
Installation Notes
Professional installation is recommended. Long tube header installation on a VQ35 platform requires lifting the engine or dropping the subframe on most chassis, and O2 sensor harness extensions are required to relocate the primary sensors to the new bung positions. This is not a driveway job for most builders.
Product Details
Brand: ISR Performance
Product: HGC Long Tube Headers
Part Number: IS-SSHD-VQ35
Fitment: Nissan 350Z, 370Z, Infiniti G35, G37 (including G35X and G37X AWD variants)
Engines: VQ35DE, VQ35HR, VQ37VHR
Material: 304 brushed stainless steel with heavy duty flanges
Design: Long tube with stepped primaries and High Ground Clearance (HGC) collector
O2 Sensor Bungs: 2 per header, downstream of collector (harness extension required)
AWD Compatibility: Yes (G35X, G37X)
Key Benefits: Retained low and mid range torque, improved top end horsepower, increased ground clearance vs traditional long tubes, factory O2 sensor compatibility